refactor(error): Give caller control over suggestion

clap_builder/src/builder/value_parser.rs

@@ -2,6 +2,7 @@ use std::convert::TryInto;
 use std::ops::RangeBounds;
 
 use crate::builder::Str;
+use crate::builder::StyledStr;
 use crate::util::AnyValue;
 use crate::util::AnyValueId;
 
@@ -2104,7 +2105,7 @@ where
 ///         Arg::new("current-dir-unknown")
 ///             .long("cwd")
 ///             .aliases(["current-dir", "directory", "working-directory", "root"])
-///             .value_parser(clap::builder::UnknownArgumentValueParser::suggest("-C"))
+///             .value_parser(clap::builder::UnknownArgumentValueParser::suggest_arg("-C"))
 ///             .hide(true),
 ///     ]);
 ///
@@ -2122,13 +2123,31 @@ where
 /// ```
 #[derive(Clone, Debug)]
 pub struct UnknownArgumentValueParser {
-    arg: Str,
+    arg: Option<Str>,
+    suggestions: Vec<StyledStr>,
 }
 
 impl UnknownArgumentValueParser {
     /// Suggest an alternative argument
-    pub fn suggest(arg: impl Into<Str>) -> Self {
-        Self { arg: arg.into() }
+    pub fn suggest_arg(arg: impl Into<Str>) -> Self {
+        Self {
+            arg: Some(arg.into()),
+            suggestions: Default::default(),
+        }
+    }
+
+    /// Provide a general suggestion
+    pub fn suggest(text: impl Into<StyledStr>) -> Self {
+        Self {
+            arg: Default::default(),
+            suggestions: vec![text.into()],
+        }
+    }
+
+    /// Extend the suggestions
+    pub fn and_suggest(mut self, text: impl Into<StyledStr>) -> Self {
+        self.suggestions.push(text.into());
+        self
     }
 }
 
@@ -2145,13 +2164,26 @@ impl TypedValueParser for UnknownArgumentValueParser {
             Some(arg) => arg.to_string(),
             None => "..".to_owned(),
         };
-        Err(crate::Error::unknown_argument(
+        let err = crate::Error::unknown_argument(
             cmd,
             arg,
-            Some((self.arg.as_str().to_owned(), None)),
+            self.arg.as_ref().map(|s| (s.as_str().to_owned(), None)),
             false,
             crate::output::Usage::new(cmd).create_usage_with_title(&[]),
-        ))
+        );
+        #[cfg(feature = "error-context")]
+        let err = {
+            debug_assert_eq!(
+                err.get(crate::error::ContextKind::Suggested),
+                None,
+                "Assuming `Error::unknown_argument` doesn't apply any `Suggested` so we can without caution"
+            );
+            err.insert_context_unchecked(
+                crate::error::ContextKind::Suggested,
+                crate::error::ContextValue::StyledStrs(self.suggestions.clone()),
+            )
+        };
+        Err(err)
     }
 }
 

clap_builder/src/error/mod.rs

@@ -718,7 +718,7 @@ impl<F: ErrorFormatter> Error<F> {
                     let mut styled_suggestion = StyledStr::new();
                     let _ = write!(
                         styled_suggestion,
-                        "'{}{sub} --{flag}{}' exists",
+                        "'{}{sub} {flag}{}' exists",
                         valid.render(),
                         valid.render_reset()
                     );
@@ -727,7 +727,7 @@ impl<F: ErrorFormatter> Error<F> {
                 Some((flag, None)) => {
                     err = err.insert_context_unchecked(
                         ContextKind::SuggestedArg,
-                        ContextValue::String(format!("--{flag}")),
+                        ContextValue::String(flag),
                     );
                 }
                 None => {}

clap_builder/src/parser/parser.rs

@@ -1521,6 +1521,7 @@ impl<'cmd> Parser<'cmd> {
                 self.start_custom_arg(matcher, arg, ValueSource::CommandLine);
             }
         }
+        let did_you_mean = did_you_mean.map(|(arg, cmd)| (format!("--{arg}"), cmd));
 
         let required = self.cmd.required_graph();
         let used: Vec<Id> = matcher

tests/builder/error.rs

@@ -219,7 +219,10 @@ fn unknown_argument_option() {
         Arg::new("current-dir-unknown")
             .long("cwd")
             .aliases(["current-dir", "directory", "working-directory", "root"])
-            .value_parser(clap::builder::UnknownArgumentValueParser::suggest("-C"))
+            .value_parser(
+                clap::builder::UnknownArgumentValueParser::suggest_arg("-C")
+                    .and_suggest("not much else to say"),
+            )
             .hide(true),
     ]);
     let res = cmd.try_get_matches_from(["test", "--cwd", ".."]);
@@ -229,7 +232,8 @@ fn unknown_argument_option() {
     static MESSAGE: &str = "\
 error: unexpected argument '--cwd <current-dir-unknown>' found
 
-  tip: a similar argument exists: '---C'
+  tip: a similar argument exists: '-C'
+  tip: not much else to say
 
 Usage: test [OPTIONS]
 
@@ -247,9 +251,10 @@ fn unknown_argument_flag() {
         Arg::new("libtest-ignore")
             .long("ignored")
             .action(ArgAction::SetTrue)
-            .value_parser(clap::builder::UnknownArgumentValueParser::suggest(
-                "-- --ignored",
-            ))
+            .value_parser(
+                clap::builder::UnknownArgumentValueParser::suggest_arg("-- --ignored")
+                    .and_suggest("not much else to say"),
+            )
             .hide(true),
     ]);
     let res = cmd.try_get_matches_from(["test", "--ignored"]);
@@ -259,7 +264,8 @@ fn unknown_argument_flag() {
     static MESSAGE: &str = "\
 error: unexpected argument '--ignored' found
 
-  tip: a similar argument exists: '---- --ignored'
+  tip: a similar argument exists: '-- --ignored'
+  tip: not much else to say
 
 Usage: test [OPTIONS]